configure: use $libdir/dri as default for VA-API

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
diff --git a/configure.ac b/configure.ac
index bef5753..59b90e6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1806,9 +1806,9 @@
 
 AC_ARG_WITH([va-libdir],
     [AS_HELP_STRING([--with-va-libdir=DIR],
-        [directory for the VA libraries @<:@default=`pkg-config libva --variable=driverdir`@:>@])],
+        [directory for the VA libraries @<:@${libdir}/dri@:>@])],
     [VA_LIB_INSTALL_DIR="$withval"],
-    [VA_LIB_INSTALL_DIR=`pkg-config libva --variable=driverdir`])
+    [VA_LIB_INSTALL_DIR="${libdir}/dri"])
 AC_SUBST([VA_LIB_INSTALL_DIR])
 
 dnl